Which area would be best for our stay in Lisbon?

We will be travelling to Lisbon for a week in over the summer. We will need to be near Parque Nacios near the bridge on first few days of the trip for a conference. I think it’s called the MEO Arena.

My goal was to go with my partner to the conference and see that area then vist the rest of Lisbon. What area is central for us to go between and be able to see the whole city. We also want to see Belem.

The metro is 1.45 euro. Area is pretty much nice view and a mall. Belem is totally on other side of city. It will cost $15 by uber. I’d stay more central if you want to see the "city". Parque is more of a bedroom community with new builds that looks like any other place in the world. But defintily worth a visit.